John says that he writes his first epistle to those who believe in Jesus, "that you may know that you have eternal life" (1 John 5:13). But John's epistle is far more than a test for genuine salvation. In this introduction to John's first epistle, we observe John's concern for the transmission of apostolic doctrine to subsequent generations of believers in the church. We also note that, because of the attacks of false teachers, John's purpose that we may "know" we have eternal life is also that we may discern whether others have it as well. We will note the date, author, provenance, and general backdrop of the letter, with special attention given to the first four verses.